Variable impression



1969 A. GARDELLA VARIABLE IMPRESSION 2 Sheets-Sheet 1 Filed NOV. 8, 1967 BUB GU [E DUUHQDDDUUU UH: UUDUUUUDUD UH: UQUUUUUUUD DD JNVENTOR ANTHONY GARDELLA BY ATTORNEY Dec. 23, 1969 RD 3,485,336

VARIABLE IMPRESSION Filed Nov. 8, 1967 2 Sheets-Sheet 2 [1 [13cm g [I] EJEJEJEJEJE] [1E1] SE11 [:1 [QUEBEC] EIUEJ 'EIU INVENTOR ANTHONY GARDELLA BY AT TORNEJ Y United States Patent US. Cl. 197-49 5 Claims ABSTRACT OF THE DISCLOSURE A differential spacing typewriter employs a spring as a hammer actuating power source, but that source must be strong enough for the most heavy impression. Therefore, a variable drag spring is used to retard or suppress the speed or force with which the hammer strikes certain characters. The retarding variable drag spring is adjustable in its retarding intensity, and the main power source spring is adjustable in its intensity. The keys which operate large size characters negate the action of the retarding variable drag spring to allow full hammer impression. Otherwise the variable drag spring operates to the degree to which it has been initially biased by operator selection.

Background of the invention The typewriter is basically an ofiice writing instrument. It was conceived as a mechanical substitute for handwriting in a variety of ofiice writing tasks such as correspondence, reports, and other similar efforts. Its product is usually an original and a few carbon copies.

The internationally known Varityper machine is a differential spacing typewriting device which looks and operates very much like the typewriter. Its keyboard is of standard arrangement, but confines the keys to three banks instead of the usual four. It types directly on paper or on duplicating masters, and the work can be seen in progress just as in the ordinary typewriter. There is not much further resemblance between the differential spacing typewriting machine and the ordinary typewriter, and this invention relates principally to machines of the difierential spacing type. The name Varityper is the registered trademark of Varityper Corporation, New Jersey, USA.

A common typewriter employs a plurality of hammers, each with a very limited number of type font characters, usually consisting of the capital and lower case of the same letter of the alphabet. The differential spacing machine, on the other hand, employs an anvil which will hold a type font. Each type font bears a grouping having a particular style, point size and horizontal spacing. The machine anvil pivots the type font to place a selected character in alignment with the hammer of the machine for imprinting. The imprinting is between metal parts. The hammer is metal and the type font is metal. Therefore, the impression pressure applied to a particular type font becomes important. The variety of types that can be used on differential spacing typewriting machines range in size from quite tiny to relatively large, and in weight from light to bold face. Consequently, variance in the force with which the hammer presses the paper against the type, referred to as impressions, is needed for the variance in size and weight of types.

The difierential spacing machines prior to the present invention have provided a degree of control for this purpose, and reference is made to US. Patent 1,918,300, issued July 18, 1933 for a disclosure of a prior system as one such control system.

Summary of the invention An advantage of this invention is that the hammer is powered by a device which delivers a predetermined power level. The device is variable by a control means in order that the amount of impact may be preset to provide the necessary impact below corresponding to the largest area size character of a particular type font in use. This adjustment is done to insure sufiicient power to properly impress the image requiring the most total pressure.

It is then an object of the invention to provide a variable load which may be applied to the hammer to counteract the force of the impression power whenever needed. The load is a subtraction from the powel level.

The object is to retard or suppress the speed or force with which the hammer strikes certain characters, eliminating variations in the density of impression due to character size.

Finally, it is the intent of this invention to apply the subtracting force as a function of actuation of the type font to place the smaller area characters in position for impact by the hammer.

Thus, the hammer is conditioned to provide suflicient force for the most severe conditions, but a reducing or suppression force may be placed to counteract the driving force in those lesser area type font situations where less force is desirable. The amount of suppression may be adjusted.

Description of drawings FIGURE 1 is a top plan of a differential spacing typewriting machine in which the present invention is employed.

FIGURE 2 is a schematic representation of the hammer and keyboard of the FIGURE 1 machine, together with the essential operating parts concerned with this invention set forth in operative relationship.

Description of the preferred embodiment FIGURE 1 of the drawings is provided in order to relate the parts shown in FIGURE 2 into an understandable, workable environment. Although the principles of this invention are applicable to other typewriting machines, a differential spacing typewriter 10 of the type internationally known by trademark Varityper is used as an illustration of the invention.

A carriage 12 carries rollers 14 and 15 for holding and advancing paper upon which typing is being performed.

Increment spacing on the differential spacing machine is well known and understood among those skilled in the typing machine art, but may be further understood by reference to companion application Ser. No. 681,334, entitled Tabulation Governor Control, filed concurrently herewith,

A hammer 18 and an anvil 19 are positioned for mutual abutment to create a printing impression. The illustrated type of machine employs a removable and replaceable type front 20 carried on the anvil 19. The type font 20 is shown in FIGURE 2 separate from the anvil 19. The type font has a plurality of raised impression characters thereon, and the machine 10 as known and understood in the typing machine art employs means to align a selected one of the characters on the type font in an anvil position for impression impact by the hammer 18. The anvil 19 serves as a track upon which the type font 20 shuttles in order to place the selected character in the position to be struck by the hammer and hence is referred to as placing the character in an anvil position. The operating structure is better seen in FIGURE 2.

A drive means for urging the hammer in an impression impact direction is illustrated in the form of a heavy driving spring 22. The hammer 18 is drawn to a cocked position ready to be released in a striking blow after alignment of the selected character to the anvil position. Thereafter, the hammer 18 is released to impact against the selected character. If paper or other media is properly placed between the hammer and the anvil'19, an impression will be made. There are several ways in which the hammer 18 may be cocked and then released for making such impression, and one improved structure is illustrated in application Ser. No. 681,337 entitled Hammer Actuator Mechanism Cycle filed concurrently herewith. The manner of cocking and releasing hammer 18 is not a part of this invention and therefore the structure and mechanism is eliminated from the drawing in order to better illustrate the principles of this invention.

The drive means is characterized by being adjustable to a plurality of driving conditions whereby a drive force may be selected for providing an impact suitable for impression of the character of the type front having the greatest surface area. The type font 20 will have a complete set of characters, some of which are of considerably larger area than others. The extremes may be represented by the capital letter W in bold face, and the period or the lower case letter i. It will be obvious that the necessary pressure to make a proper imprinting of the bold faced letter W will take much more force than for the smaller size characters.

For the purpose of establishing sufficient pressure to provide the necessary impact force for the greatest demand, an impression control lever 24 operates through a linkage 25 to operate a companon set of anchor levers 27 and 29. Spring 22 is conected to lever 29 at a point 30. Lever 29 is mounted on a pivot 32, and lever 27 on a pivot 34. The two levers are mutually joined by a pivot 36, Means to allow pivots 32 and 34 to move relative to one another is provided (not illustrated) in order that the connecting point 30 may be advanced and retracted by pivotal shifting of the lever 27 to shift the lever 29. A scale 38 provides a reference for setting lever 24. The operator may select the degree of tension to be applied to the spring 22 by causing point 30 to move away from the tail end of hammer 18 Where it is connected at point 40. Then, according to the setting of the handle 24, whenever the hammer 18 is released it will fly forward to strike the selected character on the type font 20 with the released energy of the spring 22.

Having established the maximum amount of striking power for the hammer 18, it will be apparent that such power will be in excess whenever the small punctuation marks or narrow increment letters are selected for positioning into the anvil position. Therefore, according to this invention, a drive suppression means is provided for applying a retarding drag load to hammer 18. The drive suppression means is characterized by being adjustable to a plurality of drag load conditions whereby a drag load may be selected for negating a portion of the drive force and thereby modifying the hammer impact to a lesser intensity. The principal drive suppression means is illustrated in a form of a spring 42 having two opposite end portions. It is not sutficient, of course, to provide the spring 42 with a constant drag factor. If this were done, the hammer would have a uniform striking power amounting to the force of the spring 22 less the force of the spring 42. Such would not accomplish the variable force required for uniform printing.

Spring 42 is anchored at one end portion to the tail end connection 40 of hammer 18, and at the other end portion to a mounting pin 43 on a swingable lever 44. Lever 44 is pivotally hung upon a carriage 46 by means of a pivot hanger 47. Carriage 46 is mounted by a pivot 49 upon the frame of the machine, and is moved in a limited guided path by a linkage 51 operated by means of a suppression control lever 53. Lever 53 is operator controlled at the keyboard of machine 10.

As carriage 46 is swung about the pivot 49, the pin 43 is moved toward or away from point 40 of hammer 18, albeit in a circular path, and will alter the suppression power of spring 42 according to the degree of such initial bias. The strength of the spring 42 and the amount of the movement of the pin 43 are related such that the proper degree of suppression is obtained.

Not all characters are to be suppressed however. If the swingable lever 44 were free to pivot about the pivot hanger 47, the spring 42 would be ineffective to provide any suppression. On the other hand, if it were retained and not allowed to swing, then once again suppression would be uniform. In order to make the suppression selective, an established portion of machine 10 which is employed for another purpose, is utilized to connect and disconnect the swingable lever 44 from the carriage 46 at proper times.

The machine 10 is a differential spacing machine. This means that escapement mechanism is connected to the carriage by a selected one of a plurality of gears, each of which establishes the degree of escapement to be provided for the particular type font being employed. Then, within the framework of the established escapement gear ratio, an escapement mechanism, much in the original Galileo principle, is employed to allow the established escapement to take place. The escapement is a well known structure in the typewriting machine art, and hence is not illustrated in the drawings. A flying dog is employed in such escapement devices to establsh the escapement. The flying dog is carried by an escapement wheel until brought to a stop by abutment against a stop means. Thus, this machine 10 provides a plurality of stops located at various positions in the path of the flying dog in order to provide the necessary degree of escapement. Normally the escapement is in two, three or four increments, although a separate stop device is often used to provide single increment spacing.

A rod 55 operated through linkage 56 from the various keys which have three-increment spacing, is employed to extend to the stop apparatus which is not illustrated, removing the selected stop from its position in front of the escapement flying dog. Therefore, the rod 55 is rotated only whenever those keys, such as the keys M and O illustrated in FIGURE 2, are actuated by the operator. Lines representing linkage are indicated by the reference number 58. Linkage 58 is never actuated by the twoincrement characters, such as i, f and l.

A finger 59, slideably carried upon the rod 55 by means of a bushing 60, is employed as the control device for either releasing or restraining the lever 44 in relationship to the actuation of rod 55 by linkage 58.

A spring 61 urges finger 59 along the rod 55. A drive lever combination 62 provides an abutment for spring 61, and a drive translation for the finger 59 from the rod 55. Upon actuation of the linkage 56 to rotate the rod 55 in a counter-clockwise direction indicated by the arrow in FIGURE 2, finger 59 will move downwardly.

The carriage 46 is equipped with a depending guide arm 63. Finger 59 and guide 63 remain in contact by reason of the yieldability of finger 59 provided by the bushing 60 and spring 61.

The swingable lever 44 has a return leg 65 which extends down beyond the normal position of finger 59, and therefore, finger 59 provides an interference lock to prevent swing movement of the lever 44 under the urging of the springs 22 and 42. Hence, upon setting of the carriage 46 to establish the desired degree of bias tension in the spring 42, release of the hammer 18 will be retarded to the degree of the established bias. However, if bias is not desired, such as whenever the three and four incremental characters are to be impressed, the linkage 58 causes the finger 59 to move downwardly and thereby release the swingable lever 44 from its interference locking condition. Then, the spring 42 becomes ineffective and the full striking force of the spring 22 may be impressed upon the hammer 18.

Whenever the hammer 18 is to be suppressed, however. the rod 55 is not rotated because it is not interconnected with the keys, such as the keys controlling letters i and 1. Then the full selected degree of suppression is obtained.

A spring 67, of relatively light intensity, is supplied to return the lever 44 to its lockable position immediately upon return of the hammer 18 to its cocked position, thus establishing the mechanism for the next selection of suppression or no suppression.

Whereas the present invention has been shown and described herein in what is conceived to be the best mode contemplated, it is recognized that departures may be made therefrom within the scope of the invention which is, therefore, not to be limited to the details disclosed herein, but is to be afforded the full scope of the invention as hereinafter claimed.

What is claimed is: 1. In a typewriting machine having a single impression striking hammer, a type font with a plurality of separate raised impression characters thereon, and a keyboard with a plurality of keys with means responsive to key operation to align a selected one of said characters in an anvil position for impression impact by said hammer, the provision of means to vary the impression impact of said hammer upon a selected type character comprising:

drive means for urging said hammer in an impression impact direction, said drive means characterized by providing a drive force suitable for impression of the character of said type font having the greatest surface area; a suppression spring, means for holding said spring in a position for applying a retarding drag load to said hammer and thereby modify said hammer impact to a lesser intensity;

means responsive only to selected keys actuated for larger area characters, to release said means for holding said suppression spring and thereby negate said suppression drag load for those characters only; and

means to restore said means for holding said spring to said holding condition upon completion of each key actuation and resultant hammer stroke;

whereby, said hammer is fully powered for all large area characters, and power is subtracted to apply lesser impact for smaller area characters.

2. A typewriting machine as defined in claim 1, further characterized in that:

said drive means is manually adjustable by an operator accessible control to a plurality of driving conditions whereby a drive force may be selected for providing an impact suitable for impression of the character of said type font having the greatest surface area; and

the means for holding the suppression spring is an anchor manually adjustable by an operator accessible control to a plurality of drag load positions whereby a drag load may be selected for negating a portion of said drive force and thereby modifying said hammer impact to a lesser intensity. 3. In a typewriting machine as defined in claim 2, said drive means being a spring; and

means for providing a degree of tension upon said spring which will thereby develop said selected drive force. 4. In a typewriting machine as defined in claim 2, said hammer having a pivot support, said hammer spaced on opposite sides of said pivot support as a first class lever, one end being an impression carriage, and the other a drive end;

a spring having one end attached to said drive end;

a first linkage means for providing a shiftable anchor;

said spring having a second end attached to said anchor;

control linkage from a keyboard control area to said first linkage means for manually selecting the anchor position;

the suppression spring having one end attached to said drive end;

a second linkage means for providing a shiftable anchor for said suppression spring;

said suppression spring having a second end attached to said anchor in a position to cause said spring to oppose the drive spring; and

control linkage from a keyboard control area to said second linkage means for manually selecting the anchor position.

5. In a typewriting machine having an impression striking hammer, a type font with a plurality of raised impression characters thereon, some of which have one increment value, some two increment value, and some three or more increment value; a plurality of keys arranged in a keyboard, and means for alignment of a character of said type font into hammer anvil position upon pressing a key corresponding to said character; and, advancing means for moving an impression receiving media an increment value corresponding to the character advanced to said anvil position, the improvement which comprises:

a drive means for urging said hammer in an impression impact direction, said drive means characterized by being adjustable on a preset basis to one of a plurality of driving conditions whereby a drive force may be selected for providing an impact suitable for impression of the character of said type font having the greatest surface area;

a drive suppression having one portion connected to said hammer, an anchor, a second portion controlled by said anchor, said drive suppression means subtracting from the power of said drive means only whenever said anchor holds said drive suppression means in an active position; and

means for releasing said anchor control for all keys of three increment value as a key for such character is operated to thereby negate all suppression of the hammer for such character.

References Cited UNITED STATES PATENTS 1,918,300 7/1933 Trego 19749 2,051,112 8/1936 Spaloss 19749 3,151,722 10/1964 Salto 197-17 3,239,049 3/1966 Voit 197--17 XR 3,382,963 5/1968 Cralle et a1. 19717 XR EDGAR S. BURR, Primary Examiner US. Cl. X.R. 197-17 

